Plugin for Horizontal Riule

[aldrinjenson]

Feature Request

Is your feature request related to a problem? Please describe.

It's a bit frustrating that typing "---" doesn't automatically convert it into a horizontal rule. This is a common markdown feature that users expect in text editors.

Describe the solution you'd like

I would like "---" to automatically transform into a horizontal rule (HR) when typed into the editor. This would enhance the user experience and align with markdown's intuitive formatting.

Describe alternatives you've considered

Alternatives considered:

1. Manually adding a horizontal rule using the toolbar or context menu.
2. Using additional shortcuts or commands to insert horizontal rules.

While these work, they are not as seamless as typing "---" and having it auto-convert.

Additional context

This feature is present in many markdown editors and would be a great addition to BlockNote. It makes the editor more user-friendly and intuitive for markdown-savvy users.

Bonus

• I'm a [sponsor](https://github.com/sponsors/YousefED) and would appreciate if you could look into this sooner than later 💖

[aldrinjenson]

cc @bgeils